file_plan9.go

     1  // Copyright 2011 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package net
     6  
     7  import (
     8  	"errors"
     9  	"io"
    10  	"os"
    11  	"syscall"
    12  )
    13  
    14  func (fd *netFD) status(ln int) (string, error) {
    15  	if !fd.ok() {
    16  		return "", syscall.EINVAL
    17  	}
    18  
    19  	status, err := os.Open(fd.dir + "/status")
    20  	if err != nil {
    21  		return "", err
    22  	}
    23  	defer status.Close()
    24  	buf := make([]byte, ln)
    25  	n, err := io.ReadFull(status, buf[:])
    26  	if err != nil {
    27  		return "", err
    28  	}
    29  	return string(buf[:n]), nil
    30  }
    31  
    32  func newFileFD(f *os.File) (net *netFD, err error) {
    33  	var ctl *os.File
    34  	close := func(fd int) {
    35  		if err != nil {
    36  			syscall.Close(fd)
    37  		}
    38  	}
    39  
    40  	path, err := syscall.Fd2path(int(f.Fd()))
    41  	if err != nil {
    42  		return nil, os.NewSyscallError("fd2path", err)
    43  	}
    44  	comp := splitAtBytes(path, "/")
    45  	n := len(comp)
    46  	if n < 3 || comp[0][0:3] != "net" {
    47  		return nil, syscall.EPLAN9
    48  	}
    49  
    50  	name := comp[2]
    51  	switch file := comp[n-1]; file {
    52  	case "ctl", "clone":
    53  		fd, err := syscall.Dup(int(f.Fd()), -1)
    54  		if err != nil {
    55  			return nil, os.NewSyscallError("dup", err)
    56  		}
    57  		defer close(fd)
    58  
    59  		dir := netdir + "/" + comp[n-2]
    60  		ctl = os.NewFile(uintptr(fd), dir+"/"+file)
    61  		ctl.Seek(0, io.SeekStart)
    62  		var buf [16]byte
    63  		n, err := ctl.Read(buf[:])
    64  		if err != nil {
    65  			return nil, err
    66  		}
    67  		name = string(buf[:n])
    68  	default:
    69  		if len(comp) < 4 {
    70  			return nil, errors.New("could not find control file for connection")
    71  		}
    72  		dir := netdir + "/" + comp[1] + "/" + name
    73  		ctl, err = os.OpenFile(dir+"/ctl", os.O_RDWR, 0)
    74  		if err != nil {
    75  			return nil, err
    76  		}
    77  		defer close(int(ctl.Fd()))
    78  	}
    79  	dir := netdir + "/" + comp[1] + "/" + name
    80  	laddr, err := readPlan9Addr(comp[1], dir+"/local")
    81  	if err != nil {
    82  		return nil, err
    83  	}
    84  	return newFD(comp[1], name, nil, ctl, nil, laddr, nil)
    85  }
    86  
    87  func fileConn(f *os.File) (Conn, error) {
    88  	fd, err := newFileFD(f)
    89  	if err != nil {
    90  		return nil, err
    91  	}
    92  	if !fd.ok() {
    93  		return nil, syscall.EINVAL
    94  	}
    95  
    96  	fd.data, err = os.OpenFile(fd.dir+"/data", os.O_RDWR, 0)
    97  	if err != nil {
    98  		return nil, err
    99  	}
   100  
   101  	switch fd.laddr.(type) {
   102  	case *TCPAddr:
   103  		return newTCPConn(fd), nil
   104  	case *UDPAddr:
   105  		return newUDPConn(fd), nil
   106  	}
   107  	return nil, syscall.EPLAN9
   108  }
   109  
   110  func fileListener(f *os.File) (Listener, error) {
   111  	fd, err := newFileFD(f)
   112  	if err != nil {
   113  		return nil, err
   114  	}
   115  	switch fd.laddr.(type) {
   116  	case *TCPAddr:
   117  	default:
   118  		return nil, syscall.EPLAN9
   119  	}
   120  
   121  	// check that file corresponds to a listener
   122  	s, err := fd.status(len("Listen"))
   123  	if err != nil {
   124  		return nil, err
   125  	}
   126  	if s != "Listen" {
   127  		return nil, errors.New("file does not represent a listener")
   128  	}
   129  
   130  	return &TCPListener{fd: fd}, nil
   131  }
   132  
   133  func filePacketConn(f *os.File) (PacketConn, error) {
   134  	return nil, syscall.EPLAN9
   135  }
   136
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